The invention generally relates to the flow-through, high-shear mixers and cavitation apparati that are utilized for processing heterogeneous and homogeneous fluidic mixtures through the controlled formation of cavitation bubbles and uses the energy released upon the implosion of these bubbles to alter said fluids. The device is meant for preparing mixtures, solutions, emulsions and dispersions with the particle sizes that can be smaller than one micron, particle and nanoparticle synthesis and improving composition, mass and heat transfer and is expected to find applications in pharmaceutical, food, oil, chemical, fuel and other industries.
More particularly, the device relates to the modification of fluids composed of different compounds by using the implosion energy of cavitation bubbles to improve the homogeny, viscosity, and/or other physical characteristics of the fluids, as well as, alter their chemical composition, and obtain upgraded or altered products of higher value.
Cavitation can be of different origins, for instance, acoustic, hydrodynamic or generated with laser light, an electrical discharge or steam injection. (Young, 1999; Gogate, 2008; Mahulkar et al, 2008) Hydrodynamic cavitation comprises the vaporization, generation, growth, pulsation and collapse of bubbles which occur in a flowing liquid as a result of a decrease and subsequent increase in the hydrostatic pressure and can be achieved by passing the liquid through a constricted zone at sufficient velocity. Cavitation onsets after the hydrostatic pressure of the liquid has decreased to the saturated vapor pressure of the liquid or its components and is categorized by a cavitation number Cv. Cavitation ideally begins where Cv equals 1, where a Cv less than 1 indicates a high degree of cavitation. Other important considerations are the surface tension and size of bubbles and the number of cavitation events in a flow unit. (Gogate, 2008; Passandideh-Fard and Roohi, 2008).
The eventual collapse of the bubbles results in an localized increase in pressure and temperature. The combination of elevated pressure and temperature along with vigorous mixing supplied by the hydrodynamic cavitation process triggers and accelerates numerous reactions and processes. These actions enhance the reaction yield and process efficiency by means of the energy released upon the collapse of the cavitation bubbles. Such enhanced reaction yield and process efficiency has found application in mixing, emulsification and the expedition of chemical reactions. While extreme pressure or heat can be disadvantageous, the outcome of controlled cavitation-assisted processing has been shown to be beneficial.
When fluid is processed in a flow-through cavitation mixing device at a suitable velocity, the decrease in hydrostatic pressure results in the formation of cavitation bubbles. Small particles and impurities in the liquid serve as nuclei for these bubbles. When the cavitation bubbles relocate to a high-pressure zone they will implode within a short time. The collapse of bubbles is asymmetrical because the surrounding liquid rushes in to fill the void forming a micro jet that subsequently ruptures the bubble with tremendous force. The implosion is accompanied by a significant jump in both the local pressure and temperature up to 1,000 atm and 5,000° C., respectively, and the formation of shock waves. (Suslick, 1989; Didenko et al, 1999; Suslick et al, 1999; Young, 1999) The released energy activates atoms, molecules or radicals located in the bubbles and surrounding fluid, initiates reactions and processes and dissipates into the surrounding fluid. The implosion may be accompanied by the emission of UV radiation and/or visible light, which promotes photochemical reactions and generates radicals (Sharma et al, 2008; Zhang et al, 2008; Kalva et al, 2009).
Numerous flow-through hydrodynamic cavitation devices are known. See, for example, U.S. Pat. No. 6,705,396 to Ivannikov et al, U.S. Pat. Nos. 9,290,717, 7,314,306, 7,207,712, 7,086,777, 6,802,639, 6,502,979, 5,969,207, 5,971,601 5,492,654 and 5,969,207 to Kozyuk, U.S. Pat. Nos. 8,042,989 and 7,762,715 to Gordon et al., U.S. Pat. No. 7,815,810 to Bhalchandra et al, and U.S. Pat. No. 7,585,416 to Ranade et al.
U.S. Pat. No. 7,086,777 to Kozyuk discloses a device for creating hydrodynamic cavitation in fluids which includes a flow-through chamber intermediate an inlet opening and an outlet opening. The flow-through chamber having an upstream opening portion communicating with the inlet opening and a downstream opening portion communicating with the outlet opening. The cross-sectional area of the upstream opening portion being greater than the cross-sectional area of the upstream opening portion. At least two cavitation generators located chamber for generating a hydrodynamic cavitation field downstream from each respective cavitation generator.
In contrast to sonic or ultrasonic cavitation devices, the flow-through hydrodynamic apparatuses do not require using a vessel. The efficiency of sonic or ultrasonic processing performed in a static vessel is insufficient because the effect diminishes with an increase in distance from the radiation source. The achieved fluid alterations are not uniform and occur at specific locations in the vessel, depending on the frequency and interference patterns. Thus, processing fluids via sonic or ultrasonic cavitation does not offer an optimized method.
At the present time, with energy costs rapidly rising, it is highly desirable to reduce both treatment time and energy consumption to secure a profit margin as large as possible. However, the prior art techniques do not offer the most efficient and safest methods of blending, emulsifying, altering or upgrading fluids in the shortest time possible. An advanced, compact, and highly efficient device is particularly needed at pharmaceutical plants and feedstock processing locations and refineries, where throughput is a key factor. The present invention provides such a device while upgrading products expeditiously.